Bangaii-One side of face has become black

[vtecintegra]

I've had a pair of Bangaii Cardinals for around six months. They appeared to be bonded from the beginning. I noticed the last couple of days one seemed to be staying in one spot in the back of the tank, and not eating. I figure he may be carrying eggs. Today it came towards the front, and I saw the left side of his head is very dark, doesn't seem to be using the pectoral fin on that side, and the other one is somewhat harassing it. Any ideas? Tank is peaceful with: yellow tang, bonded fire fish, possum wrasse, pink streaked wrasse, pair of grammas, yellow clown goby, blue chromis. I also was just watching them, and the other which is the female, is getting really close and shimmying.

 

[Jay Hemdal]

I've had a pair of Bangaii Cardinals for around six months. They appeared to be bonded from the beginning. I noticed the last couple of days one seemed to be staying in one spot in the back of the tank, and not eating. I figure he may be carrying eggs. Today it came towards the front, and I saw the left side of his head is very dark, doesn't seem to be using the pectoral fin on that side, and the other one is somewhat harassing it. Any ideas? Tank is peaceful with: yellow tang, bonded fire fish, possum wrasse, pink streaked wrasse, pair of grammas, yellow clown goby, blue chromis. I also was just watching them, and the other which is the female, is getting really close and shimmying.

Weird - nothing specific comes to mind other than a general injury.
Is the other side completely normal? Is there a sharp line between the dark and normal section, or does it just sort of gradually change over? A sharp line is an indication of nerve damage.
Jay

 

[vtecintegra]

Sharp line. Other side completely normal. Has me stumped. Don't want to lose this fish with it bonded to the other one.

 

[Jay Hemdal]

Sharp line. Other side completely normal. Has me stumped. Don't want to lose this fish with it bonded to the other one.

Well, fish with neurological damage will often show darkening of the skin with a distinct line between that and normal skin - very similar to how in people, when you get shingles, it radiates only along certain nerve pathways, and there is a sharp demarcation line between nerves.

I've seen this in cichlids and occasionally other species, but I do not know what causes the nerve damage to begin with - disease or injury?

If that is the case (I'm not certain that it is) then waiting it out is the only thing to do. Even if it isn't that issue, this symptoms isn't one of the infectious issues that can be treated.

Jay